java springboot项目树结构递归查询
记录工作
本文记录树结构递归查询,像菜单栏和部门
首先需要一张表
CREATE TABLE `sys_dict` (
`id` int NOT NULL AUTO_INCREMENT,
`parent_id` int NOT NULL,
`name` varchar(100) COLLATE utf8mb4_bin NOT NULL,
PRIMARY KEY (`id`) USING BTREE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;
INSERT INTO sys_dict (parent_id,name) VALUES
(0,'中国'),
(1,'云南省'),
(1,'四川省'),
(1,'广西省'),
(1,'贵州省'),
(1,'广东省'),
(2,'昆明市'),
(2,'文山市'),
(2,'红河州'),
(2,'玉溪市');
INSERT INTO sys_dict (parent_id,name) VALUES
(3,'成都市'),
(3,'广都市'),
(3,'绵阳市'),
(3,'南充市'),
(4,'桂林市'),
(5,'贵阳市'),
(6,'东莞市'),
(7,'五华区'),
(8,'砚山县');
接下来就是实体类啦
package com.example.demotest.entity;
import lombok.Data;
import java.util.List;
/**
* Description :
* Copyright : Copyright (c) 2022
* Company :
*
* @author Dshzs月
* @version 1.0.0
* @createTime 2022年11月29日 13:55:00
*/
@Data
public class SysDict {
private String id;
private String parentId;
private String orgName;
/** 子类菜单数据 */
private List<SysDict> childMenu;
}
后面接controller
@GetMapping("/menu")
public List<SysDict> findMenu() {
return recursionService.findMenu();
}
@Service
public class RecursionServiceImpl implements RecursionService {
@Autowired
private RecursionMapper recursionMapper;
@Override
public List<KeyValueItemVo> tree() {
List<SysDict> dictList = recursionMapper.list();
List<KeyValueItemVo> resultList = new ArrayList<>();
dictList.forEach(oneLevelDict -> {
KeyValueItemVo result = new KeyValueItemVo(oneLevelDict.getId(), oneLevelDict.getOrgName());
// 3、递归整理子级字典
result.setItems(getChildren(oneLevelDict.getParentId(), dictList));
resultList.add(result);
});
return resultList;
}
private SysDict getMenuTree(SysDict result, List<SysDict> list) {
for (SysDict menu : list) {
//如果父类主键等于传过来实体类的ID
if (Objects.equals(menu.getParentId(), result.getId())) {
if (result.getChildMenu() == null) {
result.setChildMenu(new ArrayList<>());
}
// 递归调用
result.getChildMenu().add(getMenuTree(menu, list));
}
}
return result;
}
到此本文就结束了